Project Leyland Mini Clubman

As our Clubman project continues to grow in scale, we find plenty to be pleased about while digging below the paint and laying bare the true state of the metal beneath.

The decision to go for a full respray uncovers some minor repairs that are needed to our Mini’s original offside sill.

Last issue we explained how a couple of localised repairs had bloomed into a total respray for our Mini Clubman. In a large part, that was down to the difficulty we had in getting a good colour match on the paint given that the panels on the car had been touched up in the past, no two panels appeared to be exactly the same colour, and nobody could tell us what the original shade had been!

Clearly, a total respray was going to increase considerably the scale of the project, and hence its cost. It also promised to throw up more repair work than originally envisaged, because even on a low-mileage car such as this, removing the paint is almost guaranteed to lay bare a number of earlier transgressions. However, one of the reasons I was happy to take this chance was that I had faith in the basic originality and soundness of the Mini’s structure, and I believed that it was a car which really deserved to be done properly.

And so it proved. In fact, we did not uncover any sign of previous welding, and no trace of rot. That is not to say it was perfect, but it did make for a very satisfying car on which to work. The major tasks prior to painting were really confined to two areas – the offside sill which had suffered a minor ding in the past and been poorly repaired plus had a very minor bit of rust at one end, and the tail of the car which had suffered from a slightly bigger knock at some point in its life. We’ll get on to that rear end next issue, but this time around we will concentrate on how panel beater Alan Denne sorted the sill.

In all fairness to the Mini, given that the offside A-panel which we replaced last issue had been one of the very few visible areas of rust on the car, it was no surprise that the end of the sill right below it should be a little crusty too. It was nothing major, just a minor hole in the outer skin where it sat over the floor-to-sill reinforcement bracket under the A-post. However, further back along the sill Alan could feel a lump in the side profile below the door. Cleaning this back with a sanding disc revealed some filler, plus a couple of small holes in the skin.

It looked like this area had been dented and poorly repaired rather than had rusted out, and sanding the rest of the panel back to bare metal only reinforced that view because elsewhere it was all shiny steel. We did note that although this sill had been painted, the paint had been applied over underseal. On the other side of the car it was the other way around, with black underseal on top of the paint. Fortunately, stripping that side back did not reveal any rust or previous damage, and showed that this was indeed a rarity – a Mini now more than 45 years old that still had its original sills, and did not need them replaced.

1 This was the damage halfway along the offside sill – it had been dented and repaired with filler, but beneath this it was now holed in an area that was no longer than 4in.

2 And this was the other area that was a little crusty – right at the front of the sill below the A- post. That round hole further back is part of the floor-to- sill reinforcement bracket.

3 First Alan took careful measurements of the existing sill panel in three places: the flange at the top under the door, the vertical face, and the bit that folds under at the bottom.

7 This was the initial cut, and it revealed nothing but solid metal behind. Fortunately, the large drain holes in a Mini sill mean that it will be easy to inject wax into the cavity afterwards.

6 After checking that the repair section extended beyond all rust, Alan then marked the sill up with chalk so that when he drew around the patch, the lines would be more easily visible.

4 These were carefully transferred to a sheet of Zintec steel, scribed out and cut. (Zintec is metal plate that has been electrolytically coated with a thin layer of zinc for rust protection.)

5 The new section was then bent roughly to shape. The key thing here was to get a nice and straight fold line, as the exact angle could be tweaked on the car.

8 The flange at the top then had to be removed from the sill’s top panel. Alan thinned it with a grinding disc in the angle grinder first to minimise any distortion, then chiselled off the remains.

9 Finally, because he was going to butt weld in the new section rather than overlap the joins, the hole to be filled was cut carefully to the size of the repair patch using tin snips.

10 Watching an expert use a gas welder is mesmerising, and since there are so many folds in the metal along the sill, distortion of the metal from the heat is going to be negligible.

11 Those drain holes also provide access to the rear of the panel being repaired, so if the position of the patch needs to be tweaked slightly, it can be moved easily both in and out.

13 Finally, after all the welding was completed and the area cleaned up with a sanding disc, this was the sill nearly ready for prepping and painting – a lovely neat repair.

12 At this point, Alan realised he had not punched plug weld holes in the top flange, and had to drill them out with a spot weld cutter. He blamed Simon for distracting him!

14 And this was the rust hole at the front of the sill after a little more digging about. It was not extensive, though a little more needs to come off at this stage and the structure beneath cleaned up before the welding can commence.

16 And finally, cleaning back the nearside sill showed that everything there was perfectly solid and totally original, which is really quite amazing on a 45-year old Mini!

15 The repair techniques here were essentially the same as they were for the repair further back, so we are leaping ahead a little here to show what the finished article looked like.